VLA detection of OH absorption from the elliptical galaxy NGC 1052

Omar, A. ; Anantharamaiah, K. R. ; Rupen, M. ; Rigby, J. (2002) VLA detection of OH absorption from the elliptical galaxy NGC 1052 Astronomy & Astrophysics, 381 (1). L29-L32. ISSN 0004-6361

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Official URL: http://www.aanda.org/articles/aa/abs/2002/01/aadi0...

Related URL: http://dx.doi.org/10.1051/0004-6361:20011604


VLA observations of OH absorption towards the elliptical galaxy NGC 1052 are presented. Both OH lines, at 1665 and 1667 MHz, were detected in absorption towards the center of NGC 1052. The hyperfine ratio of the two OH lines ( τ1667/ τ1665) is 2.6±0.8 as compared to 1.8 expected for the excitation under LTE conditions for an optically thin cloud. The column density of OH is estimated to be 2.73(±0.26)×1014 cm -2 assuming Tex~10K. The centers of both the OH lines are redshifted from the systemic velocity of the galaxy by ~173 km s -1. The velocity of OH line coincides with the velocity corresponding to the strongest HI absorption. We suggest that OH absorption is arising from a molecular cloud falling towards the nucleus. The OH line, though narrower, is found to be within the much broader and smoother H 2O megamaser emission. The possible link between OH/HI and H 2O emission is discussed.

Item Type:Article
Source:Copyright of this article belongs to European Southern Observatory.
Keywords:Galaxies: Active, Galaxies: Individual: NGC 1052; Galaxies: ISM; Radio Lines: Galaxies
ID Code:28009
Deposited On:15 Dec 2010 12:36
Last Modified:17 May 2016 11:12

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